David J. Johns

Diet or Exercise Interventions vs Combined Behavioral Weight Management Programs: A Systematic Review and Meta-Analysis of Direct Comparisons

Weight loss can reduce the health risks associated with being overweight or obese. However, the most effective method of weight loss remains unclear. Some programs emphasize physical activity, others diet, but existing evidence is mixed as to whether these are more effective individually or in combination. We aimed to examine the clinical effectiveness of combined behavioral weight management programs (BWMPs) targeting weight loss in comparison to single component programs, using within study comparisons. We included randomized controlled trials of combined BWMPs compared with diet-only or physical activity-only programs with at least 12 months of follow-up, conducted in overweight and obese adults (body mass index ≥25). Systematic searches of nine databases were run and two reviewers extracted data independently. Random effects meta-analyses were conducted for mean difference in weight change at 3 to 6 months and 12 to 18 months using a baseline observation carried forward approach for combined BWMPs vs diet-only BWMPs and combined BWMPs vs physical activity-only BWMPs. In total, eight studies were included, representing 1,022 participants, the majority of whom were women. Six studies met the inclusion criteria for combined BWMP vs diet-only. Pooled results showed no significant difference in weight loss from baseline or at 3 to 6 months between the BWMPs and diet-only arms (–0.62 kg; 95% CI –1.67 to 0.44). However, at 12 months, a significantly greater weight-loss was detected in the combined BWMPs (–1.72 kg; 95% CI –2.80 to –0.64). Five studies met the inclusion criteria for combined BWMP vs physical activity-only. Pooled results showed significantly greater weight loss in the combined BWMPs at 3 to 6 months (–5.33 kg; 95% CI –7.61 to –3.04) and 12 to 18 months (–6.29 kg; 95% CI –7.33 to –5.25). Weight loss is similar in the short-term for diet-only and combined BWMPs but in the longer-term weight loss is increased when diet and physical activity are combined. Programs based on physical activity alone are less effective than combined BWMPs in both the short and long term.

Weight change among people randomized to minimal intervention control groups in weight loss trials

Evidence on the effectiveness of behavioral weight management programs often comes from uncontrolled program evaluations. These frequently make the assumption that, without intervention, people will gain weight. The aim of this study was to use data from minimal intervention control groups in randomized controlled trials to examine the evidence for this assumption and the effect of frequency of weighing on weight change.

Dietary patterns, cardiometabolic risk factors, and the incidence of cardiovascular disease in severe obesity.

The longitudinal associations between a dietary pattern (DP) and cardiometabolic risk factors and cardiovascular disease (CVD) incidence were investigated in a cohort of adults with severe obesity.

Clinical effectiveness of very-low-energy diets in the management of weight loss: a systematic review and meta-analysis of randomized controlled trials.

Guidelines suggest that very‐low‐energy diets (VLEDs) should be used to treat obesity only when rapid weight loss is clinically indicated because of concerns about rapid weight regain.

Identifying dietary patterns by using reduced rank regression

1. Wells JC, Treleaven P, Cole TJ. BMI compared with 3-dimensional body shape: the UK National Sizing Survey. Am J Clin Nutr 2007;85:419–25. 2. Sawaya AL, Martins PA, Baccin Martins VJ, Florêncio TT, Hoffman D, do Carmo P, et al. Malnutrition, long-term health and the effect of nutritional recovery. Nestle Nutr Workshop Ser Pediatr Program 2009;63(9):5–105. 3. Pond CM, Ramsay MA. Allometry of the distribution of adipose tissue in Carnivora. Can J Zool 1992;70:342–7. 4. Ong KK, Ahmed ML, Emmett PM, Preece MA, Dunger DB. Association between postnatal catch-up growth and obesity in childhood: prospective cohort study. BMJ 2000;320:967–71. 5. Schroeder DG, Martorell R, Flores R. Infant and child growth and fatness and fat distribution in Guatemalan adults. Am J Epidemiol 1999;149:177–85. 6. Bennett FI, Walker SP, Gaskin P, Powell CA. Fasting levels of serum glucose, cholesterol and triglyceride at age eleven to twelve years in stunted and non-stunted Jamaican children. Acta Paediatr 2002;91:903–8. 7. Cameron N, Wright MM, Griffiths PL, Norris SA, Pettifor JM. Stunting at 2 years in relation to body composition at 9 years in African urban children. Obes Res 2005;13:131–6. 8. Leonard WR, Sorensen MV, Mosher MJ, Spitsyn V, Comuzzie AG. Reduced fat oxidation and obesity risks among the Buryat of Southern Siberia. Am J Hum Biol 2009;21:664–70 9. Wells JC, Chomtho S, Fewtrell MS. Programming of body composition by early growth and nutrition. Proc Nutr Soc 2007;66:423–34.

Tracking of a Dietary Pattern and Its Components over 10-Years in the Severely Obese

Understanding how dietary intake changes over time is important for studies of diet and disease and may inform interventions to improve dietary intakes. We investigated how a dietary pattern (DP) tracked over 10-years in the Swedish Obese Subjects (SOS) study control group. Dietary intake was assessed at multiple time-points in 2037 severely obese individuals (BMI 41±4 kg/m2). Reduced rank regression was used to derive a dietary pattern using dietary energy density (kJ/g), saturated fat (%) and fibre density (mg/kJ) as response variables and score respondents at each follow-up. Tracking coefficients for the DP, its key foods and macronutrient response variables and corrected for time-dependent and time-independent covariates were calculated using generalised estimating equations to take into account all available data. The DP tracking coefficient was moderate for women (0.40; 95% CI: 0.38–0.42) and men (0.38; 95% CI: 0.35–0.41). Of the eleven foods key to this DP, fruit and vegetable intakes had the strongest tracking coefficient for both sexes. Fast food and candy had the lowest tracking coefficients for women and men respectively. Scores for an energy dense, high saturated fat, low fibre density DP appear moderately stable over a 10-year period in this severely obese population. Furthermore, some food groups appear more amenable to change while others, often the most healthful, appear more stable and may require intervention before adulthood.

Clinical effectiveness of very-low-energy diets in the management of weight loss

Guidelines suggest that very‐low‐energy diets (VLEDs) should be used to treat obesity only when rapid weight loss is clinically indicated because of concerns about rapid weight regain.

Clinical effectiveness of very-low-energy diets in the management of weight loss: a systematic review and meta-analysis of randomized controlled trials: Clinical effectiveness of very-low-energy diets H. M. Parretti et al.

Guidelines suggest that very‐low‐energy diets (VLEDs) should be used to treat obesity only when rapid weight loss is clinically indicated because of concerns about rapid weight regain.

Clinical effectiveness of very low calorie diets. Systematic review and meta-analysis of randomised controlled trials

Very low calorie diets (VLCDs) are an option for the management of obesity, but are not used in primary care. This abstract presents an ongoing review to examine whether VLCDs could be an effective option for GPs to manage obesity. Literature databases were searched from database inception to February 2013. Studies were included if they were randomised controlled trials that recruited overweight or obese adults, with or without comorbidities. The intervention needed to incorporate a VLCD and comparator could be a no intervention control or an intervention that could be given in primary care. The primary outcome was weight change at 12 months from baseline. Secondary outcomes were HbA1c, lipids, and blood pressure and we recorded adverse events. We included 11 studies in the analysis which randomised 425 participants to VLCD and 349 participants to a comparator. Compared with a behavioural weight loss programme, VLCDs achieved an additional −4.1 kg (−7.3 to −0.8) greater weight loss at 12 months. Using baseline observation carried forward (BOCF), the differencewas −3.4 kg (−6.7 to −0.05). The difference in weight loss using BOCF at 18–24 months was −1.6 kg (−3.3 to −0.01) and at 42–60 months was −1.5 kg (−4.0 to 1.0). Data on secondary outcomes, adverse events and subgroup analyses will be available for an updated abstract and be presented at the conference. We will conclude on whether VLCDs appear safe and effective and hence a useful option for achieving weight loss in primary care.

Effect of behavioural techniques and delivery mode on effectiveness of weight management. Systematic review, meta-analysis and meta-regression

E-mail: Jamie.hartmann-boyce@phc.ox.ac.uk Summary A systematic review, meta-analysis and meta-regression were conducted to evaluate the effectiveness of behavioural weight management programmes and examine how programme characteristics affect mean weight loss. Randomized controlled trials of multicomponent behavioural weight management programmes in overweight and obese adults were included. References were obtained through systematic searches of electronic databases (conducted November 2012), screening reference lists and contacting experts. Two reviewers extracted data and evaluated risk of bias. Thirtyseven studies, representing over 16,000 participants, were included. The pooled mean difference in weight loss at 12 months was −2.8 kg (95% confidence interval [CI] −3.6 to −2.1, P < 0.001). I indicated that 93% of the variability in outcome was due to differences in programme effectiveness. Meta-analysis showed no evidence that supervised physical activity sessions (mean difference 1.1 kg, 95% CI −2.65 to 4.79, P = 0.08), more frequent contact (mean difference −0.3 kg, 95% CI −0.7 to 0.2, P = 0.25) or in-person contact (mean difference 0.0 kg, 95% CI −1.8 to 1.8, P = 0.06) were related to programme effectiveness at 12 months. In meta-regression, calorie counting (−3.3 kg, 95% CI −4.6 to −2.0, P = 0.027), contact with a dietitian (−1.5 kg, 95% CI −2.9 to −0.2, P < 0.001) and use of behaviour change techniques that compare participants’ behaviour with others (−1.5 kg, 95% CI −2.9 to −0.1, P = 0.032) were associated with greater weight loss. There was no evidence that other programme characteristics were associated with programme effectiveness. Most but not all behavioural weight management programmes are effective. Programmes that support participants to count calories or include a dietitian may be more effective, but the programme characteristics explaining success are mainly unknown.